Electromagnetic audible signal



i 5, 1944. s. M. KENERSON 2,357,743

ELECTROMAGNETIC AUDIBLE SIGNAL Filed April 2, 1941 2 Sheets-Sheet 1 Sept. 5, 1944.

S. M. KENERSON ELECTROMAGNETIC AUDIBLE SIGNAL Filed April 2, 1941 2 Sheets-Sheet 2 ha /2: 01 Siam/9; /7. Mme/ .90

Patented Sept. 5, 1944 UNITED STATES PATENT OFFICIE 2,357,743 ELECTROMAGNETIC AUDIBLE SIGNAL Stanley M. Kenerson, Springfield, Mass assignor to The Standard Electric Time Company, Springfield, Mass., a corporation of Connecticut Application April 2, 1941, Serial No. 386,441

4 Claims.

I acter referred to which may be produced at a low cost for manufacture and which may be relied upon to effectively perform over long periods of use.

Another object of the present invention is to provide a superior audible signal of the character referred to in whicha construction and arrangement of parts is employed which guards against the undue wear of the guide-means for a reciprocating armature and aflords ready adlustment.

A still further object of the present invention is to provide a superior audible signal for operation by a pulsating electric current in which is employed a. striker responding with high force to the action of relatively-weak magnetism.

Still another object of the present invention is to provide a device of the character referred to wherein a movable magnetic core-piece is substantially axially aligned with a fixed magnetic core-piece and in which also the two said core-pieces may approach each other closely when the audible signal is energized without requiring excessive length, to thereby minimize the dimensions of the device for a given degree of power.

With the above and other objects in view, as will appear to those skilled in the art from the present disclosure, this invention includes all features in the said disclosure which are novel sation of current-flow in the energizing-coil;

Fig. 3 is a view in' rear' elevation of the electromagnetic audible signal of the preceding figures; Fig. 4 is a view partly in side elevation and partly in central-longitudinal section of the coreunit detached;

Fig. 5 is a transverse sectional view taken on the line 5- of Fig. 4 but on a larger scale;

Fig. 6 is a perspective view of the reciprocating core-piece or striker detached; and

Fig. 7 is a perspective view of the stationary core-piece, together with the adjacent cap, and lock-nut, parts of the unit being shown in central-longitudinal section.

The particular electromagnetic audible signal herein chosen for purposes of illustrating the present invention includes a frame I ll which'may be conveniently formed of cast iron and includes I I! by means of a clamping-screw l6.

Secured to the rear face of the frame III by means of screws H or the like is a metallic assembly-plate I8 which is of substantially-rec- "tangular form in elevation and which has its upper end bent forwardly to provide a guardfiange IS. The assembly-plate i8 is also formed with a substantially-rectangular central aperture 20 which is spanned by an insulating-plate 2| of fibre or the like. As shown, the said insulating-plate may be secured to the assembly-plate l8 by four (more or less) tubular rivets 22.

Mounted against the rear face of the insulating-plate 2| above referred to are two vertically-extending and laterally-spaced-apart terminal-plates 23 and 24, each of which maybe secured in place in the location referred to by means of'a rivet such as 25, as is shown particularly well in Fig. 3. Each of the terminalplates 23 and 24 may be conveniently made of brass or other electro-conductive material and as shown, each thereof is provided adjacent its upper end with a binding-screw 25 and adjacent its lower end with a second binding-screw 21 for purposes as will hereinafter appear.

Mounted between the rearwardly-extending horizontal arms II and II of the frame I0 is an energizing-coil 28 having one of its terminalleads 29 extending to the lower binding-screw 21 of the terminal-plate 23. The other or complemental terminal-lead 36 .of -the energizingcoil 28 leads to one terminal 3| of a .copperoxide or dry-plate rectifier generally designated by the reference character 32, and requiring no detailed. description herein, inasmuch as it is a well-known device for blocking out one-hall of the wave of an alternating current. The complemental terminal 33 of the rectifier 32 is clamped to the lower binding-screw 21 of the terminal-plate 24,

When suitable leads from a source of alternating current are respectively connected to the upper binding-posts 26-26 of the terminal-plates 23 and 24, the energizing-coil 28 will receive current through the connections previously described.

Extending axially through the energizing-coil 28 is a core-tube 34 formed of non-magnetic insulating material such, for instance, as fabric impregnated with phenolic resins. The said core-tube 34 is held against axial displacement with respect to the energizing-coll 28 by means of two retaining-keys 35-35 respectively located against the upper and lower end faces of the energizing-coil 28 and fitting into suitable notches formed in the outer surface of the said core-tube,

The core-tube 34 above referred to, in addition to extending axially through the energizing-coil 28, extends also upwardly through an aligned aperture 36 in the upper horizontal arm H of the frame Ill. The lower portion of the said core-tube extends downwardly through a rearwardly-opening notch 31 formed in the lower horizontal arm [2 of the frame Ill. The lower end of the energizing-coil 28 and the adjacent retaining-key 35 are normally spaced upwardly from the upper surface of the horizontal arm 12 of the frame ill to thus crowd the upper surface of the upper key 35 against the under face of the horizontal arm I I. This spacing permits the unit comprising the energizing-coil 28, the core-tube 34 and the parts to be hereinafter described which are carriedv by the said core-tube, to be maneuvered into and out of installed positions between the two-said arms H and I2. After the installation of the unit just referred to, the said unit may be maintained in place by a spacer-block 38 preferably formed of insulating material and secured by means of one or more screws such as 33 to the upper face of the horizontal arm I2 at a point to the rear of the core-tube 34 and in position to span the rearportion of the notch 31 in the said arm l2.

At its lower end, the core-tube 34 has rigidly secured to it a cup-shaped cap 46 which may be conveniently made of aluminum and which, as is particularly well shown in Figs. 4 and '7, is formed with an axial threaded passage 4i through which extends the externally-threaded depending stem 42 of a stationary core-piece 43 formed of soft iron or other suitable magnetic material.

The said stationary core-piece 43 is housed within the lower end of the core-tube 34 and has its inner or upper end terminating about midway the axial length of the energizing-coil 28. In its upper mainly within the upper portion of the coretube 34 with capacity for vertical reciprocation therein. Like the stationary core-piece 43, the reciprocating core-piece or striker 46 is formed of iron or other suitable magnetic material. The said striker normally projects upwardly beyond the upper end of the core-tube 34, as is especially well shown in Fig. 4, and is preferably provided with a striker-head 41 which is preferably formed of chrome-nickel steel or other suitable hard and relatively-non-magnetic material. It is preferred to have the striker-head 41 of non-magnetic material to avoid the possibility of having the reciprocating core-piece or striker 46 stick to the bell 15 when the latter is formed of magnetic mawith the result that the energizing-coil 28 will receive but 60 unidirectional energizations per second.

Each energization of the energizing-0011.28 will result in the magnetization of both the stationary core-piece 43 and the reciprocating core-piece or striker 46. This magnetization will cause the striker 46 to move downwardly against the tension of the striker-spring 45 into substantially the position shown in Fig. 1 and into engagement or substantial engagement with the upper end of the stationary core-piece 43. The instant that the current through the energizing-coil ceases, the striker-spring 45 will assert itself and ,will upwardly propel the striker 46 to thus engage the striker-head 41 with the bell l5 as shownin Fig. 2. Immediately following each engagement of the striker-head 41 with the bell IS, the entire reciprocating core-piece or striker 46 will rebound downwardly, away from thesaid bell, and thus permit the latter to freely resonate.

If desired, the rectifier 32 may be omitted, and a pulsating or sinuous full-wave cuurrent fed to the energizing-coil 28, though it has been found that the best results are achieved with a low frequency which may be conveniently accomplished by the simple expedient of employing alternating current of commercial frequency and "blanketing on so to speak, part of the waves thereof.

The projecting lower end of the stem 42 of the stationary core-piece 43 is provided with a kerf or slot 48 for the reception of a screw driver or other suitable tool. Normally threaded upon the projecting lower end of the said stem 42 and in tight engagement with the under face of the cap 46 of the core-tube 34, is a lock-nut 49 which serves to hold or lock the stationary core-piece 43 in any given position of axial adjustment.

The normal or at rest position of the reciprocating core-piece 46 and consequently both the retired and projected positions of the said core-, piece, may be conveniently altered or adjusted by first loosening the lock-nut 48 and turning the stationary core-piece 43 by means of its kerf 48 to axially upwardly advance or downwardly retire the said core-piece 43 and hence, also, the core-piece 46. When the proper position of adjustment i accomplished for the core-piece 43, so that the bell l5 or other sounding device resonates properly, the core-piece 43 may be locked in this position against displacement by the vibration of the parts, by turning the lock-nut 49 into firm engagement with the under face of the cap 40 of the core-piece 43.

It is to be noted that the parts illustrated in full lines in assembled relationship in Fig. 4 may be handled as a unit and installed in and removed from the energizing-coil 28 as such a unit.

The invention may be carried out in other specific ways than those herein set forth without departing from the spirit and essential characteristics of the invention, and the present embodiments are, therefore, to be considered in all respects as illustrative and not restrictive, and all changes coming within the meaning and equivalency range of the appended claims are intended to be embraced therein.

I claim:

1. An electromagnetic vibrator-device including: an impact-abutment; a solenoid energizingcoil; a movable striker core-piece of magnetic material extending in said coil and having a striker-head adapted to strike said impact-abutment, and a thrust-abutment; a stationary corepiece of magnetic material extending. in said coil and having a thrust-abutment; a spring in said coil between and adapted to engag said thrustabutments; said striker core-piece being constructed and arranged to be vibrated only in a direction away from said impact-abutment and to stress said spring, by a pulsating electric current flowing through said coil, and said spring being constructed and arranged to vibrate said striker core-piece only toward said impact-abutment and in consequence to vibrate said strikerhead against said impact-abutment; and a current-rectifier in series with said coil and constructed and arranged to block out one-halt 01' each wave of an alternating pulsating electric current to convert it into a unidirectional pulsating electric current.

2. An electromagnetic vibrator-device including: an impact-abutment; a solenoid energizingcoil; a movable striker core-piece of magnetic material extending in said coil and having a striker-head adapted to strike said impact-abutment, and a thrust-abutment; a stationary corepiece of magnetic material extending in said coil and having a thrust-abutment; a spring in said coil between and adapted to engage said thrustabutments; said striker-head being spaced a substantial distance from said impact-abutment when said spring is in contact with said thrustabutments and said spring being constructed and arranged not to thrust said striker-head against said impact-abutment, when no electric current is flowing through said cell; said striker corepiece being constructed and arranged to be vibrated only in a direction away from said impactabutment and to stress said spring, by a pulsating electric current flowing through said coil, and said spring being constructed and arranged to vibrate said striker core-piece only toward said impact-abutment and in consequence to vibrate said striker-head against said impact-abutment; and a current-rectifier in serie with said coil and constructed and arranged to block out one-half of each wave of an alternating pulsating electric current to convert it into a unidirectional pulsating electric current.

3. An electromagnetic vibrator-device including: an impact-abutment; a solenoid energizingcoil; a movable striker-core-piece of magnetic material extending in said coil and having a striker-head adapted to strike said impact-abutment, and a thrust-abutment; a stationary corepiece oi magnetic material extending in said coil and having a thrust-abutment; a spring in said coil between and adapted to engage said thrustabutments; said striker core-piece being constructed and arranged to be vibrated only in a direction away from said impact-abutment and to stress said spring, by a pulsating electric current flowing through said coil, and said spring being constructed and arranged to vibrate said striker core-piece only toward said impact-abutment and in consequenceto vibrate said striker-head into engagement with said impact-abutment; and one or said core-pieces having a. substantiallyaxiai spring-receiving recess of a depth at least equal to a major portion of the length or said spring and of a diameter sufllcient to permit the spring to freely slide therein; and a current-rectifler in series with said coil and constructed and arranged to block out one-half of each wave of an alternating pulsating electric current to convert it into a unidirectional pulsating electric current.

4. An electromagnetic vibrator-device including: an impact-abutment; a solenoid energizingcoil; a movable striker core-piece or magnetic material extending in said coil and having a striker-head adapted to strike said impact-abutment, and a thrust-abutment; a stationary corepiece of magnetic material extending in said coil and having a thrust-abutment; a spring in said coil between and adapted to engage said thrustabutments; said striker-head being spaced a substantial distance from said impact-abutment when said spring is in contact with said thrustabutments and said spring being constructed and arranged not to thrust said striker-head against said impact-abutment, when no electric current is flowing through said coil; said striker corepiece being constructed and arranged to be vi-- brated in a direction away from said impactabutment and to stress said spring, by a pulsating electric current flowing through said coil, and said spring being constructed and arranged to vibrate said striker core-piece toward said impact-abutment and in consequence to vibrate said striker-head into engagement with said impactabutment; and one 01' said core-piece having a substantially-axial spring-receiving recess of a depth at least equal to a major portion or the length or said spring and or a diameter sumcient to permit the spring to freely slide therein.

STANLEY M. N. 

